Process for generating precision polished non-plannar aspherical surfaces

Abstract

A method for precision polishing non-planar, aspherical surfaces in substrates having variations in figure which are within an order of about ten wavelengths (10 λ) is performed by coating the non-planar, aspherical surface with a thin, uniform layer of material, single-point-diamond turning the layer to achieve a layer surface with an excellent surface figure, and etching the layer surface down into the substrate to completely remove the layer thereby transferring the excellent surface figure to the substrate.

What is claimed is: 
     
       1. A method for generating precision polished non-planar, aspherical surfaces, said method comprising the steps of: (a) generating a non-planar, aspheric surface with a base surface figure in a substrate;   (b) forming a layer on the surface with a material;   (c) single-point-diamond turning the layer to achieve a layer surface with an excellent surface figure; and   (d) etching the layer surface down into the substrate to completely remove the layer thereby transferring the excellent surface figure to the substrate.   
     
     
       2. A method as recited in claim 1 wherein: the layer is formed with a sol-gel.   
     
     
       3. A method as recited in claim 2 wherein: the sol-gel is a silica gel.   
     
     
       4. A method as recited in claim 1 wherein: the layer is formed with a photoresist material.   
     
     
       5. A method as recited in claim 1 wherein: the layer is formed with a polymeric material.   
     
     
       6. A method as recited in claim 1 wherein: the layer is formed with an emulsion.   
     
     
       7. A method as recited in claim 4 wherein: the layer is formed cataphoretically.   
     
     
       8. A method as recited in claim 6 wherein: the layer is formed cataphoretically.   
     
     
       9. A method as recited in claim 1 further comprising the step of: partially consolidating the layer prior to the step of single-point-diamond turning.   
     
     
       10. A method as recited in claim 1 wherein: the layer is formed cataphoretically.   
     
     
       11. A method as recited in claim 6 wherein: the layer of polymeric material is heated prior to the step of single-point-diamond turning to partially coalesce the layer.   
     
     
       12. A method as recited in claim 2 further comprising the step of: partially consolidating the layer of sol-gel prior to said turning step.   
     
     
       13. A method as recited in claim 12 further comprising the step of: further consolidating the layer of sol-gel after said turning step.   
     
     
       14. A method as recited in claim 6 further comprising the step of: heating the layer after said turning step to more fully coalesce the layer.   
     
     
       15. A method for fabricating molding tools for molding optical surfaces therewith, said method comprising the steps of: (a) generating a non-planar, aspheric surface with a base surface figure in a substrate;   (b) forming a layer on the surface with a material;   (c) single-point-diamond turning the layer to achieve a layer surface with an excellent surface figure; and   (d) etching the layer surface down into the substrate to completely remove the layer thereby transferring the excellent surface figure to the substrate.   
     
     
       16. A method for precision polishing a non-planar, aspherical surface with a base surface figure formed in a substrate, said method comprising the steps of: (a) forming a layer on the surface with a material;   (b) single-point-diamond turning the layer to achieve a layer surface with an excellent surface figure; and   (c) etching the layer surface down into the substrate to completely remove the layer thereby transferring the excellent surface figure to the substrate.   
     
     
       17. A method for fabricating molding tools for molding optical surfaces therewith, said method comprising the steps of: (a) generating a non-planar, aspheric surface with a base surface figure in a substrate;   (b) selecting a material which bonds to the substrate and which has a coefficient of thermal expansion which closely matches a coefficient of thermal expansion of the substrate   (c) forming a layer on the surface with the selected material;   (d) single-point-diamond turning the layer to achieve a layer surface with an excellent surface figure; and   (e) consolidating the layer to achieve a hardness which at least approximates the substrate hardness.   
     
     
       18. A method as recited in claim 1 wherein: said layer of said forming, step is formed with a single composition.   
     
     
       19. A method as recited in claim 16 wherein: said layer of said forming step is not an abrasive layer.   
     
     
       20. A method as recited in claim 16 wherein: said layer of said forming step is formed as a single-point-diamond turnable layer.